fix: container.notify type

[pedorich-n]

Notify field also accepts the value healthy:

In addition, setting Notify to healthy will postpone startup notifications until such time as the container is marked healthy, as determined by Podman healthchecks. Note that this requires setting up a container healthcheck, see the HealthCmd option for more.

From https://docs.podman.io/en/v5.3.1/markdown/podman-systemd.unit.5.html#notify-defaults-to-false
Also in code: https://github.com/containers/podman/blob/8ff491b0d9109a293847bb6a612fa195094fd6ca/pkg/systemd/quadlet/quadlet.go#L679-L691